Analyzer apparatus and control method

ABSTRACT

An analyzer apparatus includes: an ionization unit that ionizes molecules to analyze; a filter unit that forms a field for selectively passing ions generated by the ionization unit; a detector unit that detects ions that have passed through the filter unit; an ion drive circuitry that electrically drives the ionization unit; a field drive circuitry that electrically drives the filter unit; and a control unit that controls outputs of the ion drive circuitry and the field drive circuitry, wherein the control unit controls the ion drive circuitry to ramp up and down a filament voltage supplied to a filament of the ionization unit when the analyzer apparatus starts and stops.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/776,213, filed on May 15, 2018, and which is a U.S. National Stageapplication of PCT/JP2016/084120, which was filed on Nov. 17, 2016, andwhich claims the priority of JP 2015-225201, which was filed on Nov. 17,2015. The subject matter of U.S. application Ser. No. 15/776,213;PCT/JP2016/084120; and JP 2015-225201 is incorporated herein byreference.

TECHNICAL FIELD

The present invention relates to an analyzer apparatus, such as a massspectrometer.

BACKGROUND ART

International Publication WO2015/029449 discloses an analyzer apparatusthat has an ionization unit that ionizes molecules to analyze, a filterunit that selectively passes ions that have been generated by theionization unit, and a detector unit that detects ions that have passedthrough the filter unit, where the detector unit includes a plurality ofdetection elements arranged in a matrix, and the analyzer apparatusfurther includes a reconfiguration unit that switches between detectionpatterns that set which detection elements out of the plurality ofdetection elements are valid for detection. The ionization unit includesa plurality of ion sources, and the analyzer apparatus further includesa driving control unit that switches the connections of the plurality ofion sources based on changes in the characteristics of the ion sources.

SUMMARY OF INVENTION

There is ongoing demand for analyzer apparatuses such as massspectrometers to be made smaller and more precise.

One aspect of the present invention is an analyzer apparatus including:an ionization unit that ionizes molecules to analyze; a filter unit thatforms a field for selectively passing ions generated by the ionizationunit; a detector unit that detects ions that have passed through thefilter unit; an ion drive circuitry that electrically drives theionization unit; a field drive circuitry that electrically drives thefilter unit; a detector circuitry that controls the sensitivity of thedetector unit; a control unit that controls outputs of the ion drivecircuitry and the field drive circuitry; a temperature detecting unitthat detects a temperature about at least one circuitry out of the iondrive circuitry and the field drive circuitry; and a correction unitthat corrects an output setting of the at least one circuitry out of theion drive circuitry and the field drive circuitry based on thetemperature detected by the temperature detecting unit. The correctionunit may be implemented as a function of the control unit or may beimplemented as an independent unit.

The correction unit may correct (or compensate or adjust) all of therespective output settings of the ion drive circuitry and the fielddrive circuitry based on the detected temperature. Typical examples offields that selectively pass ions are an electric field, a magneticfield, and an electromagnetic field, and the field that selectivelypasses ions may include at least one of such fields.

The respective outputs of the ion drive circuitry and the field drivecircuitry minutely vary according to the temperature of the boards onwhich such circuitry are mounted or the ambient temperature about theboards, and the present inventors have found that by compensating forsuch variations, it is possible to improve the linearity of units thatare driven by these circuitry and thereby improve the detectionprecision. By adding a function that compensates or corrects the outputsof these circuitry according to temperature, it becomes possible tohouse all or part of an analyzer apparatus that includes an ion drivecircuitry, a field drive circuitry, and a control unit in a compact,handy-type housing unit.

The analyzer apparatus may include a detector circuitry that controlsthe output sensitivity (or “gain”) of the detector unit, the temperaturedetecting unit may include a function that detects the temperature aboutthe detector circuitry, and the correction unit may include a unit (orfunction) that corrects a sensitivity setting of the detector circuitrybased on the temperature detected by the temperature detecting unit.

Another aspect of the present invention is an analyzer apparatusincluding a sensor housing that houses an ionization unit, a filterunit, and a detector unit in order; a chamber in which the sensorhousing is housed; a depressurization unit that depressurizes an insideof the chamber; and a capillary that introduces gas including moleculesto analyze into the ionization unit or a periphery of the ionizationunit of the sensor housing. By connecting a capillary to the sensorhousing in which the units for measuring, such as the ionization unit,are housed, not to the chamber, it is possible to measure the gas to bemeasured in real time in a manner that is not susceptible to beingaffected by the condition in the chamber.

In addition, by providing a unit that feedback-controls a temperatureand an internal pressure of the chamber outside the sensor housing usingthe depressurization unit, it is possible to stably control the stateinside the chamber. Conventionally, the conditions inside a sensorhousing are kept constant by making the volume of the chambersufficiently larger than the sensor housing. On the other hand whenfeedback control is performed on the pressure inside the chamber, it ispreferable for the state inside the sensor housing to appear in thechamber, and for the volume Vc of the chamber to be as close as possibleto the volume Vh of the sensor housing. As one example, it is preferablefor the ratio Vc/Vh to be in a range of 1.5 to 10, with a range of 1.5to 5 even more preferable. With this method, it is possible to make thechamber smaller and to greatly reduce the size of the entire system.

Yet another embodiment of the present invention is an analyzer apparatusthat further includes a unit that stabilizes an emission current of theionization unit via the ion drive circuitry. The control unit mayinclude a function as the unit that stabilizes or the unit thatstabilizes may be an independent unit. It is possible to provide ananalyzer apparatus capable of precisely performing quantitativemeasurement by stabilizing the amount of ions inputted into the filterunit, that is, by making the amount of ions effectively constant.

Yet another aspect of the present invention is a control method of ananalyzer apparatus, the analyzer apparatus including: an ionization unitthat ionizes molecules to analyze; a filter unit that forms a field forselectively passing ions generated by the ionization unit; a detectorunit that detects ions that have passed through the filter unit; an iondrive circuitry that electrically drives the ionization unit; a fielddrive circuitry that electrically drives the filter unit; a control unitthat controls outputs of the ion drive circuitry and the field drivecircuitry; and a temperature detecting unit that detects a temperatureabout at least one circuitry out of the ion drive circuitry and thefield drive circuitry, wherein the control method includes correcting,by the control unit, an output setting of the at least one circuitrybased on the temperature detected by the temperature detecting unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 depicts the overall configuration of a gas analyzer apparatusequipped with a quadrupole mass spectrometer sensor.

FIG. 2 is a block diagram of an analyzer apparatus.

FIG. 3 is a board-level block diagram of the analyzer apparatus.

FIG. 4 is a flowchart depicting an overview of processing by theanalyzer apparatus.

FIG. 5 is a flowchart depicting processing that performs correctionaccording to temperature.

FIG. 6 is a flowchart depicting processing that stabilizes an emissioncurrent.

DESCRIPTION OF EMBODIMENTS

FIG. 1 depicts one example of a gas analyzer apparatus (or “gas analysissystem”). This analyzer apparatus (analyzer device, analyzer) 1 is amass spectrometer apparatus that incorporates a quadrupole mass sensor,and is designed to quantitatively analyze the components (molecules) ofa gas 5 that is introduced by a capillary 9. The analyzer system 1includes a quadrupole mass sensor (hereinafter simply “sensor”) 10, acontrol box 20 that drives the sensor 10 and analyzes data obtained fromthe sensor 10, a chamber 30 that houses the sensor 10, a turbo pump(turbo molecular pump) 31 and a diaphragm pump (roughing vacuum pump) 32that are connected to the chamber 30 by a connecting pipe 38 and form aunit (depressurizing unit) for depressurizing the interior of thechamber 30, a pressure gauge 33 that monitors the internal pressure ofthe chamber 30, a terminal block 35 for connecting internal and externalwiring of the apparatus, and a power supply unit 36, with thesecomponents being housed in a rectangular housing (housing unit) 50. Thesize of the housing unit 50 is about 300 mm×150 mm×150 mm, which meansthat a mass spectrometer, whose size is conventionally measured inmeters, is miniaturized into a so-called “handy size” that is compactand portable.

The sensor 10 includes an ionization unit 11 that ionizes molecules ofthe gas 5, an ion lens 12, a quadrupole filter 13, a Faraday cup 14 thatis an ion detector, and a sensor housing 19 that is cylindrical(tube-like) and in which the components 11, 12 13 and 14 are housed inthe stated order. The ionization unit 11 includes a filament that is anion source, so that thermal electrons emitted from the filament andmolecules to analyze or scan collide to ionize the molecules. Thequadrupole filter 13 is a filter unit which forms a field forselectively passing ions, and in the present embodiment, forms aquadrupole field as a field that selectively passes ions. That is, thequadrupole filter 13 has four electrodes as one set and forms aquadrupole field that has a DC component and a high frequency componentin a space surrounded by the electrodes. When ions pass along thecentral axis of the quadrupole field, the ions are repeatedly subjectedto a focusing force and a diverging force in directions that areperpendicular to the velocity. This means that at the quadrupole filter13, when the frequency of the high frequency component, the DC andhigh-frequency voltages of the quadrupole field formed in the filter 13,and the mass-to-charge ratio satisfy predetermined conditions, ions ofthe same mass-to-charge ratio will selectively pass through thequadrupole field and reach the ion detector 14, where the amount ofarriving ions is measured as an ion current.

The sensor 10 is attached to the cubic like chamber 30 so that thesensor housing 19 passes through one side wall surface of the chamber30, with substantially the entire sensor housing 19 housed inside thechamber 30. The front end of the sensor housing 19 (i.e., the ionizationunit 11-side) and the capillary 9 are connected, so that the gas 5introduced via the capillary 9 flows out into the chamber 30 via thesensor housing 19. The sensor housing 19 is connected to (fluidlycommunicated with) the chamber 30 for example by having a gap forattaching the filament of the ionization unit 11, an opening 15 providedin the vicinity of the ion detector 14 or the filter unit 13, or thelike, so that the interior of the housing 19 is kept at fundamentallythe same depressurized condition (state) as the chamber 30.

The gas 5 that has been introduced via the capillary 9 is firstintroduced into the sensor housing 19 and released into the chamber 30,before being discharged out of the system by the turbo pump 31 or thelike. This means that it is possible to precisely analyze components ofthe gas 5 supplied via the capillary 9 in real time without gas that hascirculated in the chamber 30 entering the sensor housing 19.

The rear of the sensor housing 19 is attached to the control box 20 viaan attachment pipe 28 that houses wiring. The control box 20 houses aPirani board 23 that controls the pressure gauge (pressure monitor) 33,an ion drive board 24 on which an ion drive circuitry (ion drivecircuit) 61 that electrically drives the ionization unit 11 is mounted,a field drive board 25 on which a field drive circuitry (field drivecircuit) 62, which includes an RF drive unit (RF unit) 62 r thatelectrically drives the quadrupole filter 13, is mounted, a detectorboard 26 on which a detector circuitry (detector circuit) 63, whichcontrols the output sensitivity (gain) of the ion detector 14 ismounted, a CPU 21 that performs overall control, a micro-controllerboard 22 that is connected to the CPU 21 and the respective boardsdescribed above and controls other devices such as the turbo pump 31,the fan 29 that cools the inside of the control box 20, and atemperature sensor 27 that detects the temperature of each board.

One example of the temperature sensor 27 is an infrared thermopilesensor, which detects the temperature inside the control box 20 as arepresentative value (a temperature about each circuitry, a temperaturearound each circuitry), but it is also possible to detect infrared raysfrom each board and detect the temperature of each board as thetemperature about or around (in a periphery of) the respectivecircuitry. It is also possible to attach a temperature sensor, such asan infrared sensor, a thermocouple, or a resistance temperature detectorto each board, for example, the ion drive board 24, the field driveboard 25, and the detector board 26 to acquire the temperature about oraround the circuitry mounted on the respective boards.

The analysis system 1 further includes: a vacuum and temperature controlinterface unit 55 which controls the internal pressure of the chamber 30and controls the temperature of a heater 39 that heats a vacuum systemincluding the chamber 30 and a pipe 38 that connects the chamber 30 andthe turbo pump (turbo molecular pump) 31; and a fan 53 that ventilatesthe inside of the housing 50 to control the temperature. The vacuum andtemperature control interface unit 55 includes a function for monitoringthe temperature of the chamber 30 using a temperature sensor provided tomeasure the temperature inside the chamber 30, typically an infraredthermopile sensor 34.

FIG. 2 depicts the electrical system configuration of the analyzerapparatus 1. The microcontroller (control unit) 22 includes a unit(functional unit) 22 x that operates in cooperation with a CPU subsystem21 to control the outputs of the circuitry 61, 62, and 63 according toanalytes (the objects to be measured), environmental conditions, and thelike of the sensor 10 and thereby manage the operation of the analyzerapparatus 1. The operation management unit 22 x also includes a function(unit) that changes the condition of the filter unit 13 to vary themass-to-charge ratio that passes through the filter unit 13 sequentiallyto operate the analytical device 1 in scan mode. Corresponding to theCPU subsystem 21 and the microcontroller 22, the analyzer apparatus 1includes communication interfaces 21 y and 22 y that are compliant withvarious standards, such as USB, SD cards, HDMI (registered trademark),Ethernet (registered trademark), and RS 485.

The microcontroller 22 includes a pressure and temperature control unit(pressure and temperature control function) 22 a that feedback-controlsthe degree of vacuum and temperature of the chamber 30 based oninformation obtained from the pressure monitor 33 and the vacuum andtemperature control interface unit 55. Although the pressure andtemperature control unit 22 a controls the performance of the pumps 31and 32 to control the degree of vacuum, the pressure and temperaturecontrol unit 22 a mainly controls the rotating speed of the turbomolecular pump 31 on the high vacuum side to maintain a predetermineddegree of vacuum. The pressure and temperature control unit 22 asimultaneously controls the power of the heater 39 so as to keep thetemperature of the chamber 30 constant.

When the degree of vacuum in the chamber 30 is controlled to keep theperformance of the sensor 10 constant, the larger the volume of thechamber 30, the smaller the fluctuations in the degree of vacuum, sothat conventional chambers 30 have commonly had a volume that is forexample twenty times the sensor 10 or larger. However, since the outputof the sensor 10 (the detector 14) will not change unless the gas insidethe chamber 30 is replaced, when the volume of the chamber 30 is large,the sensitivity to variation in time is low, and since a mere averagevalue of the gas in the chamber 30 is detected by the sensor 10, therehas been the drawback of reduced sensitivity to variations in thecomponents. There has been a further problem in that once the degree ofvacuum in the chamber 30 has varied due to factors such as temperature,it takes a long time to return to the desired state.

In contrast, in the present system 1, by reducing the volume of thechamber 30, it becomes possible to stabilize the measurement conditionsand solve the above problems. That is, first, by reducing the volume ofthe chamber 30, variations in the internal conditions of the chamber 30are more sensitively captured by the pressure monitor 33 and/or thetemperature sensor 34. By improving the precision of the feedbackcontrol performed based on the degree of vacuum and temperature in thechamber 30 with controlling the vacuum pumps 31 and 32 that form thedepressurization unit, it is possible to stabilize the conditions insidethe chamber 30. In addition, by reducing the volume of the chamber 30,it is possible to measure real-time variations in the gas componentsmore precisely. Also, by reducing the volume of the chamber 30, there isa further merit in that it is possible to make the analysis system 1compact enough to be portable. The capacity Vc of the chamber 30 and thevolume Vh of the sensor housing 19 should preferably satisfy thefollowing condition.1.5<Vc/Vh<10  (1)

The upper limit of Condition (1) is preferably 8, more preferably 5, andeven more preferably 3.

The pressure monitor 33 that monitors the internal pressure of thechamber 30 is configured to monitor the pressure in the region outsidethe sensor housing 19 within the chamber 30. If there is variation inthe pressure of the gas 5 supplied from the capillary 9, the effect ofthis will appear after the gas 5 has flowed out into the chamber 30 viathe sensor housing 19, and even though the chamber 30 has a low volume,this volume is still large compared to the capillary 9, which suppressessudden variations in pressure. Accordingly, since the pressurevariations that are to be monitored are reduced, the operating of thedepressurization unit configured by the vacuum pumps 31 and 32,especially the operation of the turbo pump 31 that controls targetingthe internal pressure of the chamber 30 can be moderated, which makes itpossible to more smoothly cope with variations in pressure of the gas 5supplied from the capillary 9.

The microcontroller 22 further includes a correction unit (correctionfunction, compensation function or unit, or adjustment unit) 22 b thatmakes various corrections (compensation, or adjustment) to the outputsettings of the ion drive circuitry 61 and the field drive circuitry 62and the sensitivity settings (gain setting) of the detector circuitry 63based on the temperature about or around (in the periphery of) thecircuitry detected by the temperature detection unit (temperaturesensor) 27. In this example, the correction unit 22 b corrects therespective output settings of the ion drive circuitry 61 and the fielddrive circuitry 62, and the gain setting of the detector circuitry 63 ina unit of 10° C. (in 10° C. increments) in a range from 0° C. to 80° C.by referring to a look-up table 69 in which correction amounts for thesetting values are stored in advance. In place of the look-up table 69,it is also possible to use a method, such as functions or equations,that calculates or outputs correction values.

For example, in the RF drive unit 62 r of the field drive circuitry 62,to forms the quadrupole field in the quadrupole filter 13, it isnecessary to output an RF voltage, a DC+ voltage, and a DC− voltagelinearly proportional to AMU units. However, the output (voltage and/orcurrent) of the RF drive unit 62 r slightly fluctuates according to theenvironmental temperature where the field drive circuitry 62, whichincludes the RF drive unit 62 r, is installed, so that there may be adrop in linearity with respect to AMU. This error can cause measurementerrors.

When the components included in the gas 5 are qualitatively determined,variations in the output of the RF drive unit 62 r will have littleeffect on qualitative measurements. On the other hand, when thecomponents included in the gas 5 are quantitatively determined, unlessthe linearity of the RF voltage and the like with respect to AMUs isguaranteed, there is the risk that converting the measurement results ofthe ion currents to concentrations will no longer be meaningful.Accordingly, the correction unit 22 b refers to compensation valuesoutput setting values, correction values, or differences) stored in thelook-up table 69 that have been determined in advance using theenvironmental temperature of (temperature about) the RF drive unit 62 r,and varies the output setting (base value or base curve) of the RF driveunit 62 r, in this example, changes the output setting values withrespect to AMUs depending on the temperature within a predeterminedrange, so that even if the environmental temperature varies, thelinearity with respect to AMUs, of the RF voltage, the DC+ voltage, andthe DC− voltage outputted from the RF drive unit 62 r is maintained.

Accordingly, although this analyzer 1 is a quadrupole mass spectrometer,it is possible to perform quantitative analysis that was notconventionally possible. The present invention is not limited to aquadrupole field, and when controlling, based on the characteristics ofions or molecules such as AMUs, mass-to-charge ratios, and ionmobilities, the voltage or current that form (drive) a “field” that isan electric field, a magnetic field, or an electromagnetic field thatselectively passes and/or holds ions, it is possible, by controlling orcorrecting a signal or information that controls the voltage or currentused for driving the field, relative to a temperature itself ortemperature difference based on the temperature about the circuitryoutputting the signal, to suppress the temperature dependency of thevoltage or current that drives the field, which makes it possible toform a higher precision field in the filter unit 13.

For the ion drive circuitry 61, although a sensitivity to theenvironmental temperature (temperature about the circuitry) andtendencies may differ to the field drive circuitry 62, the output of theion drive circuitry 61 may vary. At the ion drive circuitry 61, forexample, the filament voltage and/or the filament current of theionization unit 11 may fluctuate depending on the temperature, andtherefore it may be effective to correct or compensate the settings ofthese voltage and current values, for example, a base curve or basevalue, according to temperature by the correction unit 22 b. For thedetector circuitry 63, the gain of the Faraday cup and/or electronmultiplier that is the detector 14 and the amplification (gain) of theoutput signal can be corrected or compensated according to temperature.Using the same method as for the field drive circuitry 62, thecompensation unit 22 b corrects the setting values for these circuitry61 and 63 to ensure linearity.

The microcontroller (control unit) 22 further includes a stabilizingunit 22 c that stabilizes, via the ion drive circuitry 61, an emissioncurrent Ea that indicates the ionizing power of the ionization unit 11.In this example, the emission current Ea is controlled to 0.1%, that is,to an nA level. By controlling the variations in the emission current Eaof the ionization unit 11 to 1% or below, and more preferably to 0.1% orbelow, the amount of ions inputted into the filter unit 13 can be kepteffectively constant. This means that the amounts of the various ionsseparated by the filter unit 13 and detected at the detector unit 14,that is, the content (content ratios, proportions) of the gas 5, can bequantitatively determined with high precision.

The ionization unit 11 in the present embodiment is configured to outputthermal electrons using a filament. The stabilizing unit 22 c includes afirst stabilizing unit (convergence unit) 22 d, which measures an ionbox current, for example, as the emission current Ea and controls thefilament voltage Fv to ramp up or down according to a look-up table orthe like that has been set in advance so that the emission current Ea iswithin ±1% of a target current Et, and a second stabilizing unit(feedback control unit) 22 e, which shifts the filament voltage Fv by aminute amount (Δf) by feedback control so that the emission current Eais within ±0.1% of the target current Et. One example of feedbackcontrol is PID (proportional-integral-derivative control).

FIG. 3 depicts the more detailed configuration of the ion drivecircuitry 61 and the detector circuitry 63 by way of a block diagram.The ionization unit 11 includes filaments 11 f and a repeller electrode11 r disposed in an ion box 11 b. The gas 5 inputted into the sensor 10by the capillary 9 is ionized by the ionization unit 11, and thegenerated ion flow (ionized gas) 3 is guided to the field (quadrupolefield) 13 f of the filter unit 13 by the ion lens 12. Ions that havebeen separated and/or selected by the field 13 f reach the detector unit14 and are observed as an ion current flowing across the collector 14 c.

The ion drive circuitry 61 includes a driver unit 61 a that suppliespower to elements that construct the ionization unit 11 and amonitor/control unit (monitor and control unit) 61 b that monitors andcontrols the ionization unit 11. As one example, the driver unit 61 asupplies filament driving power via filament power control units 71 aand 71 b to the two filaments 11 f respectively, sets the repellervoltage of the repeller electrode 11 r, and sets the voltages of the ionbox 11 b and the ion lens 12. The filament power control units 71 a and71 b include MOSFET switches that respectively shut down the power ofthe corresponding filament immediately.

The ion drive circuitry 61 includes a circuitry 72 that measures afilament voltage Vf and a filament current If, and in the presentembodiment provides feedback via the monitor/control unit 61 b to themicrocontroller 22. The ion driver circuitry 61 further includescircuitry 73 and 74 that respectively measure the ion box current I1 andthe ion lens current I2, and in the present embodiment, provide feedbackvia the monitor/control unit 61 b to the microcontroller 22.

The filament power control units 71 a and 71 b control the voltage Vfsupplied to the respective filaments 11 f as outputs and monitor thefilament current If. As one example, the filament voltage Vf iscontrolled so as to increase or decrease in steps (ramp up or down) whenthe analyzer apparatus 1 starts and stops, and in a steady state, iscontrolled to become a voltage capable of emitting thermal electronsthat can ionize the molecules to analyze (to be measured) and iscontrolled so that the emission current Ea becomes constant. As theemission current Ea, it is possible to refer to the ion box current I1and/or the ion lens current I2. The ion box current I1 has a largecurrent value due to being close to the filament 11 f, which makes iteasy to grasp changes in the emission current Ea. On the other hand, theion box current I1 could conceivably be affected by the electronsemitted from the filament 11 f. For this reason, in the presentembodiment, by comparing the ion box current I1 and the ion lens currentI2, an emission current Ea that excludes the effects of thermalelectrons from the ion box current I1 is determined.

The filament voltage Vf is controlled so that the emission current Eabecomes constant, for example, to produce a tolerance with respect tothe target current Et of 0.1% or below, or less than 0.1% (in otherwords, the tolerance becomes the nA level). This emission currentcontrol may be realized by the stabilizing unit 22 c of themicrocontroller 22 as described above, or may be realized by themonitor/control unit 61 b of the ion driver circuitry 61.

Since the characteristics of the circuitry elements that construct theion drive circuitry 61 may exhibit minute fluctuations according to thetemperature around the circuitry, the filament voltage Vf that is theoutput of the ion drive circuitry 61 may minutely rise and fallaccording to the temperature. For this reason, the monitor/control unit61 b receives a correction signal S1, which is based on the temperatureof the ion drive circuitry 61 itself or the temperature in the peripheryof the ion drive circuitry 61, from the correction unit 22 b andcorrects the voltage that is a standard or base for the filament voltageVf.

In the same way, in the field drive circuitry 62, the RF unit (RF poweramplifier) 62 r receives the correction signal S1 and corrects theoutput settings, such as the voltage and frequency, with the RF outputas a standard or base to suppress variations due to the temperatureabout the circuitry board that includes the field drive circuitry 62.The detector circuitry 63 includes an amplifier 75 that amplifies an ioncurrent I3 obtained by the detector 14, and a gain controller 76 thatcontrols the gain of the amplifier 75, with the gain controller 76receiving the correction signal S1 and correcting the setting of thegain of the amplifier 75 based on the temperature about the circuitryboard that includes the detector circuitry 63 to suppress the influenceon the output of the amplifier 75 of the temperature about the circuitryboard. As the amplifier 75, as one example it is possible to use acombination of a TIA (transimpedance amplifier) and a VGA (variable gainamplifier) to adjust gain and have high linearity.

FIG. 4 depicts an overview of control (processing) executed by themicrocontroller (control unit) 22 of the analyzer apparatus 1 by way ofa flowchart. When the components of the gas 5 are to be monitored by theanalyzer 1, in step 81, the operation management unit 22 x causes theanalyzer apparatus 1 to operate in scan mode to sequentially detectmolecules (components) with different mass-to-charge ratios. In thisprocess, the quadrupole field 13 f of the filter unit 13 is controlledby the field drive circuitry 62 so that ions of different mass-to-chargeratios pass through the filter unit 13 in order and reach the detectorunit 14.

In step 81, scanning is repeatedly executed to monitor temporal changesin the components of the gas 5 and/or to get average values of thecomponents acquired at appropriate time intervals. In the scanning,during a scan, each time scanning is repeated or after scanning has beenrepeated an appropriate number of times, in step 82, the correction unit22 b performs a process that corrects the setting values based on thetemperatures about the respective circuitry 61 to 63, and in step 83,the stabilizing unit 22 c performs a process that keeps the emissioncurrent Ea constant.

FIG. 5 depicts the process 82 that corrects the output settings (settingvalues, basic parameters, base curves or the like) of the circuitryaccording to the temperature about the circuitry (circuits or boards) inmore detail. In step 85, the temperatures of the boards on which therespective circuitrys 61 to 63 are mounted or the temperatures in theperipheries thereof are detected. In step 86, the correction unit 22 brefers to the look-up table 69 and if it is necessary to change theoutput setting values of the ion drive circuitry 61, for example, thebasic setting values for calculating the filament voltage Vf, withrespect to the detected temperature, in step 86 a outputs an order ofcorrection (compensation signal) S1 to the ion drive circuitry 61.

In the same way, in step 87, if correction or change of the settingvalues of the field drive circuitry 62 (in the present embodiment, theRF unit 62 r) is required according to the detected temperature aboutthe circuitry, in step 87 a, an order of correction is outputted to thefield drive circuitry 62. Also, in step 88, if it is necessary tocorrect or change the sensitivity (or gain) of the detector circuitry 63according to the detected temperature about the circuitry, in step 88 a,an order of correction is outputted to the detector circuitry 63.

In this way, by correcting the output settings and/or sensitivitysettings of the respective circuitry 61 to 63 according to thetemperatures about the circuitry, it is possible, even when thetemperatures about the circuitry 61 to 63 vary, to keep the ionizationperformance of the ionization unit 11 constant, to keep the ionselecting performance of the filter unit 13 constant, and to keep thesensitivity of the detector unit 14 constant. Accordingly, it ispossible to maintain the analytical performance, even when the boards 24to 26 on which the circuitry 61 to 63 are mounted, the other boards 21to 23, and the like are housed together with the vacuum pumps 31 and 32,the heater 39, and the like inside the compact housing 50 in which thetemperature conditions are susceptible to varying. This means that it ispossible to provide a high-performance analyzer 1 with a compact size,such as a “handy-size” device. The correction unit 22 b may correct onlythe output or sensitivity of one or two circuitry, out of the circuitry61 to 63, whose output or sensitivity is greatly affected by thetemperature.

FIG. 6 depicts a process 83 that stabilizes the emission current Ea ofthe ionization unit 11 in more detail. In step 91, the operationmanagement unit 22 x sets the filament voltage Vf at a target value andthe ion drive circuitry 61 drives the ionization unit 11 at the setfilament voltage Vf. If the analyzer apparatus 1 is being activated oris preparing for stopping, the target value is set according to asequence that ramps up or down the filament voltage Vf that raises orlowers the filament voltage Vf in steps. During steady operation, inaccordance with a lifetime management schedule of the filament 11 f, ascheduled voltage that causes a predetermined emission current Ea to beobtained is set.

In step 92, the stabilizing unit 22 c calculates the difference ΔEbetween the target emission current value Et and the actual emissioncurrent value Ea. In step 93, if the difference ΔE is not below 1%, instep 94, the filament voltage Vf is increased or decreased in steps atintervals set in advance (convergence process).

In step 93, if the difference ΔE is determined to be less than 1%, theconvergence process ends, there is a transition to feedback control instep 95, and in the present embodiment a PID loop is executed. In step96, the difference ΔVf for the filament voltage Vf that is the output ofthe PID control is acquired, and the filament voltage Vf is correctedwith ΔVf. In step 97, the difference ΔE for the emission current Ea isrecalculated, and if the difference ΔE is less than 0.1% in step 98, theion drive circuitry 61 drives the ionization unit 11 at the filamentvoltage Vf set in this process.

After it has been determined in step 98 that the difference ΔE is 0.1%or higher, if the difference ΔE is less than 1% in step 99, theprocessing advances to step 95 and corrects the filament voltage Vfusing feedback control. On the other hand, when the difference ΔE is 1%or more, the processing returns to step 92 and in the convergenceprocess that corrects the filament voltage Vf by ramping up or down, theemission current Ea is caused to converge to the target value Et in ashort period of time. By carrying out this processing, it is possibleduring measurement in the steady state to set the tolerance in theemission current Ea of the analyzer apparatus 1 at less than 0.1%, whichmakes it possible to manage the emission current Ea at substantially thenA level. Accordingly, it is possible to precisely supply a constant ionflow 3 to the field 13 f for selecting ions formed in the filter unit13, which means that it is possible to provide an analyzer device 1 of atype that measures gas components by ionization, but is capable ofquantitative analysis.

Although the above describes, as the filter unit 13 of the analyzerapparatus 1, an example where a quadrupole field is formed as the field13 f for separating or selecting ions, the field 13 f may be an electricor magnetic field, such as a fan-shaped magnetic sector, amagnetic-electric double converging field, or a time-of-flight type. Thefilter unit 13 may form an electric field and a magnetic field(electromagnetic field) like a Wien filter as the field 13 f forselecting ions. The filter unit 13 may be a filter unit that forms, asthe field 13 f, an electric field for selecting ions according to ionmobility instead of the mass-to-charge ratio, for example, a non-vacuumfilter unit 13, such as a FAIMS. It is also possible to use a filterunit 13 that forms a combination of a plurality of different types offields 13 r.

Also, although the analyzer apparatus 1 described above is equipped withthe housing (housing unit) 50 in which the sensor 10, the control box20, and the vacuum pumps 31 and 32 and the like are integrated in aso-called “handy size”, it is also possible to provide the sensor 10 andvacuum system separately to the control box 20 and house respectively ineven more compact housings, and possible to accommodate a variety ofarrangements, since the circuitry can maintain their precision even whenthere are variations in temperature around the circuitry. Although acompact sensor with a size of several cm has been given as an example ofthe sensor 10, the sensor 10 may be an even more compact MEMS-typesensor. The analyzer apparatus 1 may be a handy size, or may be furtherminiaturized to a mobile terminal or a wearable size.

One of the aspects of the above is an analyzer apparatus that comprises:an ionization unit that ionizes molecules to analyze; a filter unit thatforms a field for selectively passing ions generated by the ionizationunit; a detector unit that detects ions that have passed through thefilter unit; an ion drive circuitry that electrically drives theionization unit; a field drive circuitry that electrically drives thefilter unit; a control unit that controls outputs of the ion drivecircuitry and the field drive circuitry; a temperature detecting unitthat detects a temperature about at least one circuitry out of the iondrive circuitry and the field drive circuitry; and a correction unitthat corrects an output setting of the at least one circuitry based onthe temperature detected by the temperature detecting unit. The analyzerapparatus may further comprise a handy-type housing unit that houses atleast the ion drive circuitry, the field drive circuitry, the controlunit, and the correction unit. The analyzer apparatus may furthercomprise a detector circuitry that controls an output sensitivity of thedetector unit, wherein the temperature detecting unit includes afunction that detects a temperature about the detector circuitry, andthe correction unit may include a unit that corrects a sensitivitysetting of the detector circuitry based on the temperature detected bythe temperature detecting unit.

The analyzer apparatus may further comprise a sensor housing that housesthe ionization unit, the filter unit, and the detector unit in order; achamber in which the sensor housing is housed; a depressurization unitthat depressurizes an inside of the chamber; and a capillary thatintroduces gas including the molecules to analyze into the ionizationunit or periphery of the ionization unit of the sensor housing. Thesensor housing may include an opening that connects to the chamber at avicinity of at least one of the filter unit and the detector unit, andthe analyzer apparatus may further include a unit that feedback-controlsa temperature and an internal pressure of the chamber outside the sensorhousing by the depressurization unit. A ratio Vc/Vh between a volume Vcof the chamber and a volume Vh of the sensor housing may set 1.5 to 10.The analyzer apparatus may further comprise a handy-type housing unitthat houses at least the ion drive circuitry, the field drive circuitry,the control unit, and the chamber. The analyzer apparatus may furthercomprise a unit that stabilizes an emission current of the ionizationunit via the ion drive circuitry. The field that selectively passes theions may include at least one of an electric field, a magnetic field,and an electromagnetic field. The field drive circuitry may includecircuitry that supplies an RF output to the filter unit to form avibration field.

Another aspect of the above is a control method of an analyzerapparatus. The analyzer apparatus includes: an ionization unit thationizes molecules to analyze; a filter unit that forms a field forselectively passing ions generated by the ionization unit; a detectorunit that detects ions that have passed through the filter unit; an iondrive circuitry that electrically drives the ionization unit; a fielddrive circuitry that electrically drives the filter unit; a control unitthat controls outputs of the ion drive circuitry and the field drivecircuitry; and a temperature detecting unit that detects a temperatureabout at least one circuitry out of the ion drive circuitry and thefield drive circuitry. The control method comprises correcting, by thecontrol unit, an output setting of the at least one circuitry based onthe temperature detected by the temperature detecting unit. The analyzerapparatus may further include a detector circuitry that controls anoutput sensitivity of the detector unit. The temperature detecting unitmay include a function that detects a temperature about the detectorcircuitry. The correcting may include correcting a sensitivity settingof the detector circuitry based on the temperature detected by thetemperature detecting unit. The control method may further comprisestabilizing, by the control unit, an emission current of the ionizationunit via the ion drive circuitry.

The invention claimed is:
 1. An analyzer apparatus comprising: anionization unit that ionizes molecules to analyze; a filter unit thatforms a field for selectively passing ions generated by the ionizationunit; a detector unit that detects ions that have passed through thefilter unit; an ion drive circuitry that electrically drives theionization unit; a field drive circuitry that electrically drives thefilter unit; and a control unit that controls the ion drive circuitry soas to ramp up and down a filament voltage supplied to a filament of theionization unit when the analyzer apparatus starts and stops.
 2. Theanalyzer apparatus according to claim 1, further comprising a handy-typehousing that houses at least the ion drive circuitry, the field drivecircuitry, and the control unit.
 3. The analyzer apparatus according toclaim 1, further comprising a unit that stabilizes an emission currentof the ionization unit via the ion drive circuitry.
 4. The analyzerapparatus according to claim 1, wherein the field that selectivelypasses the ions includes at least one of an electric field, a magneticfield, and an electro-magnetic field.
 5. The analyzer apparatusaccording to claim 1, wherein the field drive circuitry includes acircuitry that supplies an RF output to the filter unit to form avibration field.
 6. A control method of an analyzer apparatus, theanalyzer apparatus including: an ionization unit that ionizes moleculesto analyze; a filter unit that forms a field for selectively passingions generated by the ionization unit; a detector unit that detects ionsthat have passed through the filter unit; an ion drive circuitry thatelectrically drives the ionization unit; a field drive circuitry thatelectrically drives the filter unit; and a control unit that controlsoutputs of the ion drive circuitry and the field drive circuitry,wherein the control method comprises controlling, by the control unit, afilament voltage supplied to a filament of the ionization unit to rampup and down when the analyzer apparatus starts and stops.
 7. The controlmethod according to claim 6, further comprising stabilizing, by thecontrol unit, an emission current of the ionization unit via the iondrive circuitry.